A population based seroepidemiological survey of Chlamydia pneumoniae infections in schoolchildren

Chlamydia pneumoniae and chronic asthma: Updated systematic review and meta-analysis of population attributable risk

Background

Chlamydia pneumoniae (Cp) is an obligate intracellular human respiratory pathogen producing persisting lung infection with a plausible link to asthma pathogenesis. The population attributable risk of potentially treatable Cp infection in asthma has not been reported.

Methods

The author searched from 2000 to 2020 inclusive for previously un-reviewed and new cross sectional and prospective controlled studies of Cp biomarkers and chronic asthma in both children and adults. Qualitative descriptive results and quantitative estimates of population attributable risk for selected biomarkers (specific IgG, IgA and IgE) are presented.

Findings

No large, long-term prospective population-based studies of Cp infection and asthma were identified. About half of case-control studies reported one or more significant associations of Cp biomarkers and chronic asthma. Heterogeneity of results by age group (pediatric v adult asthma), severity category (severe/uncontrolled, moderate/partly controlled, mild/controlled) and antibody isotype (specific IgG, IgA, IgE) were suggested by the qualitative results and confirmed by meta-analyses. The population attributable risks for Cp-specific IgG and IgA were nul in children and were 6% (95% confidence interval 2%-10%, p = 0.002) and 13% (9%-18%, p<0.00001) respectively in adults. In contrast to the nul or small population attributable risks for Cp-specific IgG and IgA, the population attributable risk for C. pneumoniae-specific IgE (children and adults combined) was 47% (39%-55%, p<0.00001). In the subset of studies that reported on asthma severity categories, Cp biomarkers were positively and significantly (P<0.00001) associated with asthma severity.

Interpretation

C. pneumoniae-specific IgE is strongly associated with asthma and asthma severity, suggesting a possible mechanism linking chronic Cp infection with asthma in a subset of individuals with asthma. Infection biomarkers should be included in future macrolide treatment trials for severe and uncontrolled asthma.

Chlamydia pneumoniaeRespiratory Infections in Taiwan

To understand the epidemiology of Chlamydia pneumoniae acute infections in Taiwan, we collected 116 paired and 244 single sera from patients suspected of C. pneumoniae infection and conducted microimmunofluorescence test. Eighty-three patients (83/360, 23%) met the diagnostic criteria of current C. pneumoniae infection. The C. pneumoniae infections were significantly higher in men than in women (P< or =0.0001) and were most frequent in the group of 40-49 year-olds, and the people older than 70 years old. C. pneumoniae infection often occurred in the late autumn lasting to the cold winter and in the transition period between the spring and summer.

Acute Chlamydia pneumoniae infections in asthmatic and non-asthmatic military conscripts during a non-epidemic period

Chlamydia pneumoniae respiratory tract infections were studied in 512 male military conscripts (123 asthmatic and 389 non-asthmatic) taking part in 180-day service between July 2004 and July 2005 in Kajaani, Finland. Respiratory tract infections requiring a medical consultation were analysed prospectively. At baseline, at end of service, and during each episode of respiratory infection, blood samples were obtained for measurement of C. pneumoniae antibodies. Data concerning the clinical features of each infection episode were collected. Serological evidence of acute C. pneumoniae infection was found in 34 of the 512 conscripts with antibody data available, including 9.8% of the asthmatic subjects and 5.7% of the non-asthmatic subjects (p 0.111). A serological diagnosis could be made for 25 clinical episodes in 24 conscripts. The spectrum of respiratory tract infections included 13 episodes of mild upper respiratory tract infection and seven episodes of sinusitis, with five episodes involving asthma exacerbation. Two of three pneumonias were primary infections. Primary infections were diagnosed in five subjects, and re-infection/reactivation in 19 subjects, with the latter comprising 12 non-asthmatic subjects and seven asthmatic subjects (p 0.180). Prolonged infections were present in six asthmatic subjects and one non-asthmatic subject (p 0.001). A wide variety of respiratory tract infections, ranging from common cold to pneumonia, were associated with serologically confirmed C. pneumoniae infections. Infections were often mild, with common cold and sinusitis being the most common manifestations. Acute, rapidly resolved C. pneumoniae infections were equally common among asthmatic subjects and non-asthmatic subjects, whereas prolonged infections were more common among subjects with asthma.

Infections and vaccinations preceding childhood Guillain-Barré syndrome: a prospective study

INTRODUCTION

We performed a prospective, multicentre study in children with Guillain-Barré syndrome (GBS), diagnosed according to international criteria, to investigate the frequency and aetiology of antecedent diseases. All infections and vaccinations occurring within a 6-week period prior to the onset of GBS were documented.

MATERIALS AND METHODS

Stool cultures, standardised serological investigations and PCR analyses for 24 different infective agents were performed. Serological findings were regarded as significant if specific immunoglobulin (Ig)M or IgA antibodies were detected, if the IgM enzyme immunoassay or immunfluorescence assay findings were confirmed by immunoblot, if complement fixation test titres rose fourfold or if geometric titres were more than threefold higher than in uninfected control persons. Ninety-five children with GBS were included in the study over a 40-month period. Preceding events were reported in 82%.

RESULTS

Microbiological studies carried out on 84 patients resulted in a probable diagnosis in 46 (55%). Coxsackieviruses (15%), Chlamydia pneumoniae (8%), cytomegalovirus (7%) and Mycoplasma pneumoniae (7%) were the most frequently involved agents. Serological evidence of a Campylobacter jejuni infection was found in six patients (7%). Eight children had been vaccinated during the 6 weeks preceding the onset of GBS; in six of these children concomitant infectious diseases were reported, and in one child the time between vaccination and GBS was extremely short.

CONCLUSION

We conclude that, in contrast to adults, Campylobacter spp. does not seem to play a major role in childhood GBS in German-speaking countries. The aetiology of antecedent diseases is distributed over a wide spectrum of paediatric infectious diseases. Most of the children who had been vaccinated showed concomitant infectious diseases, thus obscuring the causative role for GBS.